[BAA 00323] Favourable close approach of asteroid 2007 TU24

[Rick]

Dear Observer,

We have a very favourable opportunity, the best for several years, to see a bright near-Earth asteroid as it approaches to within 1.4 lunar distances (535,000 km) of the Earth (closest on 2008 Jan 29 08:33 UT).  This object, discovered by the Catalina Sky Survey on 2007 October 11, is between 200 and 500 meters in diameter and is most favourably placed for observation from the UK on the night of Tuesday Jan 29/30 when it will reach magnitude 10. The object, designated 2007 TU24, has an orbital period of 2.85 yr but its axial rotation period and lightcurve amplitude are currently unknown.

Below are ephemerides suitable for observation from the UK.  Alternatively for your local ephemerides, visit the Minor Planet Center at: http://www.cfa.harvard.edu/iau/MPEph/MPEph.html

Please report observations to Roger Dymock, Director of the BAA Asteroids and Remote Planets Section (ARPS).

Richard Miles
Assistant Director, ARPS, BAA

Code Select Expand

Asteroid 2007 TU24

             Ephemeris for J77 (50.9deg N, 2.4 deg W)

Date     UT      RA       Dec      Delta    r     Elong  Ph.A   V    app. motion  Az.  Alt
       hh:mm  hh mm ss   dd mm.m     AU     AU     deg   deg   mag   "/min P.A.  deg  deg

Jan 29 17:00  07 20 00  +72 33.4   0.0041  0.987  124.1  55.7  10.3  164.3 096   207  +48
Jan 29 18:00  07 54 34  +72 06.1   0.0042  0.987  125.4  54.4  10.3  154.9 104   208  +50
Jan 29 19:00  08 25 00  +71 20.1   0.0043  0.988  126.5  53.3  10.3  145.7 112   210  +52
Jan 29 20:00  08 51 04  +70 20.8   0.0045  0.988  127.6  52.2  10.3  136.9 118   212  +54
Jan 29 21:00  09 13 03  +69 12.5   0.0046  0.988  128.6  51.2  10.4  128.7 124   214  +58
Jan 29 22:00  09 31 27  +67 58.8   0.0047  0.988  129.5  50.3  10.4  121.0 129   215  +62
Jan 29 23:00  09 46 52  +66 42.2   0.0049  0.988  130.3  49.5  10.5  114.1 133   215  +66
Jan 30 00:00  09 59 50  +65 24.3   0.0050  0.988  131.0  48.8  10.5  107.7 136   211  +71
Jan 30 01:00  10 10 50  +64 06.6   0.0052  0.988  131.7  48.1  10.5  102.0 139   200  +75
Jan 30 02:00  10 20 13  +62 49.7   0.0053  0.989  132.3  47.5  10.6   96.8 142   177  +78
Jan 30 03:00  10 28 19  +61 34.5   0.0055  0.989  132.8  46.9  10.6   92.0 144   150  +77

Jan 30 18:00  11 27 50  +47 53.3   0.0083  0.991  136.0  43.7  11.5   40.5 150   210  +16
Jan 30 20:00  11 31 27  +46 46.5   0.0087  0.991  136.0  43.6  11.6   35.9 152   227  +26
Jan 30 22:00  11 34 22  +45 45.8   0.0091  0.992  136.1  43.6  11.6   32.2 155   244  +41
Jan 31 00:00  11 36 42  +44 49.4   0.0095  0.992  136.1  43.5  11.7   29.5 158   262  +58
Jan 31 02:00  11 38 37  +43 56.2   0.010   0.992  136.2  43.4  11.8   27.6 160   293  +76

M.P.E.C. 2008-B17                                Issued 2008 Jan. 19, 07:10 UT

[MarkS]

Thanks Rick.  That's definitely one to look out for.

[MarkS]

NASA/JPL has an illustration showing its path through the constellations tonight (and tomorrow).

http://neo.jpl.nasa.gov/news/news157.html

It'll show you roughly where to look but parallax means it won't be exact.   Turn it upside down and it shows what we'll see looking North at around 9pm tonight.

[MarkS]

Well, this is what I saw looking North at 9pm:



Depressingly familiar ...

[Rick]

...and it's much the same here now.

[Mac]

Is that an Oak tree?

[MarkS]

Yes, it's an oak tree,  But what I really wanted to see was a near Earth asteroid.  I'll try again tonight ...

According to Rick's ephemerides it's still moving at 35arcsec every minute (of time) relative to the star background so it'll just appear as a streak in any photo.

[MarkS]

Picture on a new thread: http://forum.orpington-astronomy.org.uk/index.php?topic=2959

[Rick]

Good one, Mark.

The BAA Asteroids & Remote Planets Section might be interested in seeing those, particularly if you have (or can derive) good timing information on the individual frames. If you do contact them, mention that you're a member of the OAS, as the OAS (as a Society) is a member of the BAA.

[MarkS]

I've got some others but not quite so clear because some thin high level cloud came over.

I had difficulty finding it visually because either the scope alignment was wrong or the ephemerides were out.  But the ephemerides were calculated exactly for my location (I think) from the NASA/JPL site and the scope centred a nearby star (Dubhe in Ursa Major) perfectly.  I carefully set up that shot so the asteroid would pass straight through the centre of the FOV.  But it passed a long way off centre as you can see.  I must re-check my data.

[Rick]

The positions could have been out because the orbital parameters weren't quite correct, or that you don't quite know your position accurately enough, or that their code wasn't working to sufficient precision, or some combination of all three.

The object of reporting observations would be to get enough information to allow the orbital parameters to be refined. Individual frames, times (how reliably accurate can you get those?) and your exact position (OS grid reference, probably) would most likely be what they'd be after.

[MarkS]

Ah, times.

No, unfortunately, I haven't got those with any accuracy at all.  The clock on my camera is completely wrong. 

It's a good point - I should set it very accurately for the future then if an event is captured by one of my images I'll have a precise idea of when it happened.

[mickw]

Mark, are you capturing on the camera card or laptop ?
The file would have a time/date.
Mick

[Rick]

The way to get accurate timings is to determine just how inaccurate the clock in the timing device (in this case, the camera) is, and then apply the appropriate offset to each image. You could try to take an accurately-timed frame at the beginning and end of an evening's observing. There was a time the Speaking Clock was considered a suitable reference, but a digital radio-controlled clock might be better, if you could photograph its display...

Something to discuss over in "Technical" perhaps?

[Ian]

might be another reason to hook up a gps to the laptop...